1. Field of the Invention
This invention relates generally to digital cameras and, more particularly, to a digital camera for recording image data onto an unloadably loaded recording medium, such as a memory card or optical disk, and reproducing record data out of the recording medium.
2. Description of the Prior Art
The digital cameras have functions of reproducing compressed image data out of a recording medium and decompressing it into a decompressed image to be displayed on a monitor provided thereon. Some of the digital cameras have also a function of reproducing sound data out of a medium as above and outputting it via a speaker through predetermined signal processing.
Meanwhile, the parameters associated with the reproduced image and sound data vary in quality. The individual image sensors are quite different in respect of the parameter of resolution, e.g., pixel count ranges from as low as about 0.35 million to as high as nearly several hundreds of millions. In order to actually display reproduced images on a monitor, encoding has to be done so that the resolution can be matched to the image sensor. In dealing with motion image data, not only the quality of the resolution parameter but also the quality of the frame rate parameter should be taken into consideration. For motion image data, in some cases 15 still images constitute 1 second of motion image whereas in other cases 30 still images are required for 1 second of motion image. For proper speed reproduction, reproduction should be suited in frame rate. Furthermore, for reproducing sound data, the quality associated with this parameter, which may be expressed in terms of sampling rate or quantization bit count for conversion from an analog to digital signal, must be taken into account.
In this manner, the qualities of different digital cameras are greatly different from one to another in respect of resolution, frame rate, sound quality, and other parameters. However, as long as the still image, motion image or sound having been taken by one person""s digital camera is reproduced on that camera, it is satisfactory to merely have a corresponding reproduce function to a recording function of the same camera.
However, today""s digital cameras employ unloadable recording media, such as memory cards and magneto-optical disks. It is possible to commonly utilize only one recording medium between the digital cameras adopting a same scheme of recording media. This means that one can use on his or her digital camera a recording medium having been used on another""s digital camera. However, if there is superiority or inferiority in parameter quality between these cameras, the data recorded by the digital camera implementing the superior parameter quality is impossible to reproduce on a digital camera implementing on inferior parameter quality. More specifically, if one digital camera has an image sensor with a resolution quality of XGA and the other digital camera has that of VGA, image data with XGA taken by the one digital camera cannot be reproduced on the other digital camera having no XGA-compatible encoding function.
It is therefore, a primary object of the present invention to provide a digital camera which can reproduce even an image signal taken by a superior performance of another digital camera.
A signal recording/reproducing apparatus according to the present invention, comprises: an input processing circuit for performing a corresponding input process to any one of qualities of N in kind on a signal externally fetched; a recorder for recording a first signal outputted from the input processing circuit to an unloadably loaded recording medium recorded with a second signal having a quality different from the qualities of N in kind; a reproducer for reproducing either one of the first signal or the second signal from the recording medium; a quality detector for detecting a quality of a signal reproduced by the reproducer; an output processing circuit for performing output processing of M in number corresponding to respective qualities of M in kind on the reproduced signal; and an enabler for enabling any one of the output processing of M in number based on a result of detection by the quality detector, wherein the N and the M are positive integers that satisfy N less than M, and the qualities of M in kind including the quality of the second signal.
According to the present invention, when a signal is externally given, the input processing circuit performs corresponding input process to any one of the qualities of N in kind on this signal. The first signal outputted from the input processing circuit is recorded on the recording medium by the recorder. The recording medium herein is unloadably loaded and recorded with a second signal having a different quality from any of the qualities of N in kind. If a first signal or second signal is reproduced from the recording medium by the reproducer, the reproduced signal is supplied to the output processing circuit for performing corresponding output processing of M in number to the respective qualities of M in kind. On the other hand, the reproduced signal is detected in quality by the quality detector. The enabler enables any one of the output processing of M in number based on a result of detection by the quality detector.
Consequently, the reproduced signal is output-processed depending upon its quality, thus being properly outputted. Furthermore, N and M are positive integers that satisfy N less than M, and the qualities of M in kind include a quality of the second signal. Accordingly, even when the second signal has a quality that the input processing circuit is not compatible with, a reproduced signal is properly outputted. That is, according to the present invention, it is possible to properly reproduce a signal having been recorded on the recording medium by an image recording/reproducing apparatus having a higher performance than the present apparatus.
In one embodiment of the invention, the first and second signals include respective ones of quality information, and the quality detector detecting a quality of the reproduced signal according to the quality information included in the reproduced signal.
In another embodiment of the invention, the input processing circuit includes an image sensor having a first resolution to shoot a subject, the first signal being an image signal having the first resolution. On the other hand, the second signal recorded on the recording medium is an image signal having a second resolution higher than the first resolution. In the output processing circuit, a first converter converts the first resolution image signal into a third resolution image signal, and a second converter converts the second resolution image signal into the third resolution image signal. Here, the third resolution is a resolution of the monitor that is lower than the first and second resolutions. A converter selector selects either one of an output of the first converter or an output of the second converter.
In another embodiment of the invention, the input processing circuit includes a microphone to intake an external sound and an input processor to perform signal processing with a first sound quality on a sound signal taken by the microphone. The first signal is a sound signal having the first sound quality. On the other hand, the second signal is a sound signal having a second sound quality superior to the first sound quality. In the output processing circuit, a first output processor performs corresponding output processing to the first sound quality, and a second output processor performs corresponding output processing to the second sound quality. A processor selector selects either one of the first output processor or the second output processor. As a result, a desired sound is outputted.
In still another embodiment of the invention, the input processing circuit includes an image sensor to shoot a subject at a first frame rate, the first signal being a motion image signal having the first frame rate. On the other hand, the second signal recorded on the recording medium is a motion image signal having a different second frame rate from the first frame rate. The first and second signals include respective ones of frame rate information, and the reproducer reproducing either one of the first signal or the second signal into a form in compliance with the frame rate information. Due to this, the motion image signal is reproduced at a desired rate.
A digital camera according to the present invention, comprises: an image sensor for shooting object at a first frame rate; a recorder for recording a corresponding first motion image signal having the first frame rate to a subject image shot by the image sensor onto an unloadably loaded recording medium recorded with a second motion image signal having a different second frame rate from the first frame rate; a selector for selecting a desired motion image signal; a detector for detecting a frame rate of the desired motion image signal; and a reproducer for reproducing the desired motion image signal into a form in compliance with the frame rate detected by the detector.
According to the present invention, a subject is shot by the image sensor at a first frame rate. A corresponding first image signal at the first frame rate to the shot subject image is recorded on the recording medium by the recorder. The recording medium herein is unloadably loaded and recorded with a second motion image signal having a different second frame rate from the first frame rate. If a desired motion image signal is selected by the selector, the desired motion image signal is detected in frame rate by the detector. The reproducer reproduces a desired motion image signal in a suited form for the detected frame rate. That is, the desired motion image signal is reproduced at normal rate.
In one embodiment of the invention, the first and second motion image signals include frame rate information, and the detector detecting a frame rate of the desired motion image signal according to the frame rate information.
The above described objects and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.